If I had to go with any of those answers, It would be A maybe D, But im not too sure on how to decide between them. Because Einstein mentioned the sun in his theory which has a very large mass <span> 1.989 x 10 with a exponent of 30 to be exact. Hope this helped though.</span>
Answer:

Explanation:
Refractive Index: It is a measure to find how fast the light travels through a medium. It is ration of the speed of light in vacuum to speed of light in the medium. Speed of light is not constant and varies depending on the density of the medium.
In vacuum the speed of light is 300000 km/s and is denoted by c. When the light beam enters any medium the speed will decrease. Here it is given that the speed in plastic is v. Thus the refractive index(n) is given as:

It is a dimensionless no.
I think it is b , that what I would i pick
Answer:
Explanation:
Kinematics equation for first Object:
but:
The initial velocity is zero
it reach the water at in instant, t1, y(t)=0:
Kinematics equation for the second Object:
The initial velocity is zero
but:
it reach the water at in instant, t2, y(t)=0. If the second object is thrown 1s later, t2=t1-1=1.02s
The velocity is negative, because the object is thrown downwards